2008 Yamaha 50 HP Ouboard Won't Run

[usnavy8084]

New to the forum. Prior to starting the boating season, I changed all of the fuel lines starting at the tank (completely drained), primer bulb, fuel filter with water separater, up to the quick connect fitting on the engine. Added 7 gallons of new fuel and oil started engine at home. Engine ran like a watch. Added more fuel from gas station. On the water ran fine through various throttle positions for about an hour. Throttled down to idle speed, engine stopped and took almost 20 minutes to finally start. Would only run at 1/2 to WOT. Could see air in fuel line and primer bulb wouldn't hold pressure. Finally got the boat loaded and home. Threw away the Walmart POS primer bulb and bought a new quick silver primer bulb from the dealer. Primer bulb holds pressure but can still see air bubbles in fuel line. Removed fuel line from filter and stuck in gas can. Tried to start engine........... a few pops and sputters. Replaced all 3 spark plugs, still nothing. Sprayed fuel in carbs and motor runs for a short period. Removed top carburetor, disassembled (removed the jet screw plug and jet screw..........nothing plugged and very minor debris) adjusted jet screw to as found # of turns, cleaned and reassembled, reinstalled on engine. . Primed fuel bulb and still see air in fuel line but the bulb is firm engine finally fires and runs but there is still a major miss. Will only run at 1/4 throttle for about 2 minutes and dies. Disassembling the top carb did contribute to the engine finally starting. As there are 2 more carbs (obviously harder to get to) should I continue on this path or does anyone have another suggestion?

 

[99yam40]

Re: 2008 Yamaha 50 HP Ouboard Won't Run

It is easier to pull all 3 as a unit and then disassemble on work bench. At least it is on my 99 40.
Disassemble completely, clean well , blow out with compressed air.
Make sure the carbs are marked as which spot they came from and do not mix any parts between the 3.
Put back together and install, do the link and sync as the manual calls for every time reinstalling the carbs.

Make sure you flush any debris from pump and lines on motor before hooking up to the cleaned carbs

 

[usnavy8084]

Re: 2008 Yamaha 50 HP Ouboard Won't Run

It is easier to pull all 3 as a unit and then disassemble on work bench. At least it is on my 99 40.
Disassemble completely, clean well , blow out with compressed air.
Make sure the carbs are marked as which spot they came from and do not mix any parts between the 3.
Put back together and install, do the link and sync as the manual calls for every time reinstalling the carbs.

Make sure you flush any debris from pump and lines on motor before hooking up to the cleaned carbs

Thanks and I have already taken your advice....all 3 have been removed cleaned and reassembled. To add to the Walmart "Moeller" brand primer bulb saga, my brother found a pin hole in the brand new hose that came with the junk primer bulb. Cut that end off of the hose and no more air in the system. The worst of all of this seems that the I introduced the problem by using cheap parts and it has cost me in time and money!! I should have listened to my Fathers life long advice............The cheap way is the expensive way everytime!! Hope this helps somebody eles avoid an issue.

 

[usnavy8084]

Re: 2008 Yamaha 50 HP Ouboard Won't Run

Update: Top and lower carb low speed idle screws were set at 1/2 turn each with the middle carb set at 1 1/4 turns. Adjusted all 3 to 1 1/2 turns and followed RodBolts Link and Sync procedure. The motor runs great with smooth acceleration. This motor never ran this good from day one when I bought is brand new from the dealer. It would always sputter and die during idle operation especially when loading/unloading at the boat ramp. I drilled out the caps covering the idle screws so I know the carbs were set incorrectly and worse inconsistently from the factory. Hope this helps other folks.

 

[99yam40]

Re: 2008 Yamaha 50 HP Ouboard Won't Run

So called Cleaning carbs without pulling pilot screws does not clean all passages.
Not sure why they would have been set that way from factory maybe your drilling moved them if the bit hit the screw when it went through, but good to hear it is running well now.

It is important to make sure everything is in spec as the manual states, even if they were not that way when taking apart